Network infrastructures have recently been expanded, and an increasing number of content providers are producing and storing contents desired by users. Users can visit sites run by such content providers and receive desired contents.
Efficient delivery of contents requires web syndication as a scheme for delivering information produced and modified in real time on the Internet. The web syndication includes, for example, RSS (Really Simple Syndication) and ATOM, which have been proposed and adopted as standards. The RSS and ATOM have made it possible to distribute contents, and contents can be collected more efficiently by a program such as RSS Reader.
However, in mobile environments with comparatively limited resources, access to contents distributed by RSS/ATOM cannot be made in the same manner as in PC environments. In order to solve this problem, a scheme for delivering contents collected for mobile terminals in an optimized manner has been requested, and one of typical examples is DCD (Dynamic Content Delivery), the standardization of which is being conducted by OMA (Open Mobile Alliance).
The DCD seeks to provide mobile terminal users with desired contents in the most efficient manner reflecting the users' preferences. Content delivery schemes for this purpose include a pull scheme employing DCD-1 Interface and a push scheme employing DCD-2 Interface. According to existing mobile services, mobile terminals of users must access sites on the wireless Internet and search a number of depths for desired contents. In contrast, the DCD aims to deliver contents to mobile terminals of users without having to visit and search sites for contents so that users are provided with desired contents that reflect the users' preferences to the greatest extent.
The DCD technology is based on a client server model. Particularly, a DCD server adapted to deliver contents interworks with a DCD client within a terminal, which acts as a client receiving the contents. The DCD technology defines messages exchanged between the DCD server and the DCD client, and specifies a protocol for exchanging contents and messages. In order to deliver contents to the DCD client, the DCD server must receive corresponding contents from the CP (Content Provider) that stores the contents.
However, the conventional DCD technology has a problem in that the DCD server and the CP cannot collect content usage information, i.e. the amount and type of contents used by users. This makes it difficult for the DCD server and the CP to provider users with highly-preferred contents.
The fact that the DCD server and the CP cannot collect content usage information also creates a problem in that users are provided with unnecessary contents.
In other words, the DCD server and CP provide unnecessary contents since they cannot collect content usage information. This wastes the network bandwidth and degrades the content delivery efficiency of the terminals, CP, and the DCD server.